Method and associated apparatus for the standardized grading of gemstones

ABSTRACT

A method and associated apparatus ( 5 ) for the standardized grading of gemstones is provided. The system gauges the spectral response of a gemstone subject to a plurality of incident light sources ( 77, 64, 90, 92, 102 ) within an imaging apparatus. The operation of the imaging apparatus is controlled by an instruction set of a local station control data processor ( 12 ). Light energy data is captured in the form of pixel data sets via a charge coupled device of the imaging apparatus of the local station ( 8 ). The control data processor data of the local station is operably linked to analysis station ( 14 ). Gemstones qualities are analyzed by the plurality of light sources ( 92, 90, 102 ) of the imaging apparatus ( 5 ) and quantified relative to model pixel data sets of the database and recorded for future reference therein.

This application is a continuation of U.S. application Ser. No.09/085,797, filed May 28, 1998, now U.S. Pat. No. 6,020,954.

FIELD OF THE INVENTION

This invention relates to gemstone grading systems. More specifically,the present invention provides an automated gemstone grading and datamanagement system for use in appraising the value of a gemstone and touniquely identify it.

BACKGROUND OF THE INVENTION

The monetary value of diamonds, pearls, and other precious gemstones canvary considerably relative to the aesthetic features of each stone. Suchfeatures as, color, clarity, cut, shape, brilliance, etc., are importantsubjective determinants of value. For example, it is not uncommon tofind gemstones of identical size and weight varying significantly due tothe effect of such subjective determinants. As such, consistentmeasurement of these characteristics is a first step towards a reliableestimate of a gemstone's monetary value.

Presently, a variety of instruments are utilized to grade gemstones,such instruments include the simple eyeglass or loupe, as well as manysophisticated imaging instruments. Imaging instruments are commonlyutilized in evaluating the objective and subjective qualities ofgemstones, these instruments include simple ultra-violet lamps,microscopes, chelsea filters, calcite type dichroscopes, refractometers,polariscopes, spectroscopes, etc. Imaging instruments enable operatorsto visually analyze gemstones through illumination and magnification, orelectronically gauge the gemstones refraction and/or reflectioncharacteristics to incident light.

However, imaging instruments and systems are presently incapable ofproducing a reliable and reproducible index of a gemstone's objectiveand subjective qualities. The choice of imaging instrument, humanjudgment, and visual perception are all factors which impact theconsistency of gemstone appraisals. Additionally, such appraisals havebeen heretofore incapable of measuring several subjective determinantssuch as brilliance, scintillation, polish, and cut quality.

For example, traditionally, the grading of a gemstone's color fails toconsider the size of the gemstone, its transparency, flaws, degree offluorescence, a lack of standard practice in preparation of a sample,and whether or not equivalent levels of illumination were utilized. Avariety of instruments and methods for color grading rely on colorcomparison kits for visually comparing a sample, the kits are used tosubjectively assign a color based on this comparison. Since it is wellknown that human judgment and eyesight vary from person to person, suchcolor grading systems are unreliable. Some sophisticated instrumentsassign color by measuring light frequencies transmitted through orreflected from a surface, while others use reference light to evaluateshifts in color spectra and yet others convert the light frequenciesinto tri-stimulus which are used to assign a color to an object. Yet,fluorescence present in more than 50% of the diamonds and many othergemstones will shift color frequencies. Magnitude of UV radiation in alight source will therefore affect color grade. As can be appreciated,these devices have yet to achieve a level of consistency acceptable tothe gem trade.

Moreover, these devices do not offer a system of assigning a cut gradeto an object that matches any one of the several well known round andfancy gemstone cuts. Cut analysis can be improved by direct measurementsof the side, top, and bottom views of objects being analyzed. Based onthese measurements, Proportions of objects can be measured and they canbe assigned a shape, a cut grade, and sorted. The foregoing devices areincapable of precisely obtaining with certainty the minimum and maximumdimensions of a gemstone, such as girdle or table measurements.

Similarly, the clarity of a diamond and other transparent gemstones isbased on the number, size, and distribution of flaws, inclusions,bubbles, crystals, and any other foreign matter that will distract fromits internal flawless beauty. Surface defects in the form of scratches,bruting marks, naturals, and feather are also important to the qualityof a gemstone. A process for automatically identifying location, sizeand type of internal flaws in gem stones has yet to be developed.

Additionally, such subjective determinants as brilliancy andscintillation in certain gem stones is highly prized. Naturally,inconsistent lighting conditions will produce different brilliancyreadings. While a lighting standard must be developed to obtainconsistent results, it should be flexible enough to allow fordifferences in gemstones, presently, inconsistent brilliancy andscintillation valuation of gemstones is commonplace.

Such inconsistencies in evaluating the above objective and subjectivegemstone properties has encouraged the proliferation of sophisticatedcounterfeiting and synthetic gemstone industries which further obfuscatethe gemstone appraisal process. Identification or authentication ofthese objects is a primary component of a reliable gem appraisalpractice. As sophisticated counterfeiting procedures are developed toalter appearance such as laser drilling, radiation, and the substitutionof with highly reflective plastics and liquids, ever more reliableequipment and procedures are necessary to separate natural goods fromthose which have been altered, enhanced or those that are man made.Furthermore, there is well established need in the jewelry trade tofingerprint a gemstone for future identification. Gemstones removed forcleaning or sold on consignment may be switched. Insurers and consumersare interested in reclaiming lost or stolen goods recovered by police orretailers. A method is needed that will accurately measure andautomatically record many attributes of a gemstones which can be usedhierarchically to match a gemstone.

In addition to the aforementioned security concerns, presently,gemstones must be shipped or sent by a courier for appraisal or forevaluation by an interested buyer. This activity is lime consuming,expensive, and places inventory at risk. An electronic means oftransferring text, numerical and visual data that accurately representsthe various attributes of a gemstone can significantly improvetransactions while reducing associated shipping, insurance and securitycosts. This functionality requires not only communication capability buta database capability that can automate recording of text, audio andvideo information from gem analysis. The database must be secure andfully integrate inventory functions with analysis, management,retailing, and marketing of gem stones and information.

The apparatus in accordance with the present invention, provides areliable and reproducible evaluation, measurement, and recording systemfor quantifying heretofore objective and subjective gemstonecharacteristics.

SUMMARY OF THE INVENTION

A method and associated apparatus for the standardized grading ofgemstones is provided in which the spectral response of a gemstonesubject to a plurality of incident light sources is captured via acharge coupled device (CCD). An imaging apparatus employing a CCD camerais operably linked with an analysis station, the analysis stationincluding a data processor and database for processing the spectralresponse data as captured by the CCD camera in the form of pixel datasets. The database employs a library of exemplary gemstone pixel datasets as measured by the apparatus, the library data functioning torelate, compare, and distinguish the spectral response of an individualgemstone's pixel data set to the reference pixel data sets of thedatabase. The data processor of the analysis station provides aninstruction set for facilitating communication with the imagingapparatus, analyzing communicated pixel sets, and producing reports to,identify the gemstone's shape, quantify, and reliably grade heretoforesubjective qualities of gemstones. The reports are communicated from theanalysis station to the imaging apparatus for reproduction by anoperably linked local printer.

The data processor of the analysis station communicates with a controldata processor of the imaging apparatus. The control data processor ofthe apparatus provides an instruction set for automating the stepsnecessary to precisely position and operate the imaging hardware. Thecontrol data processor has local and wide area communication capabilityfor communicating captured pixel data sets to the analysis station inaddition to the hardware positioning actuation analysis instruction set.

An object of the invention is to extract consistently and accurately,size, shape, and proportion information from the side, top, and bottomimages of a gemstone using the data processing instruction set. Thisinformation is used for cut analysis, weight calculation, and forassigning a cut grade using a statistical procedure such as a cluster orlinear discriminant analysis. Cut grade analysis is based on cut gradestandards for different types of cuts and the respective proportions ofvarious dimensions of a gemstone, diamonds in particular.

Still another object of the invention is to measure color and assign acolor grade to a gemstone. This is accomplished by using an illuminantstandard such as D 55 recommended by the C.I.E. (InternationalCommission on Illumination) having a color rendition and an ultra violetcomponent that closely resembles North-Daylight. A database of thesereadings is developed for stones of different but known colors alongwith the size, cut, fluorescence and flaw information for each stone.This multivariate data is used to assign a color grade using astatistical procedure such as cluster or linear discriminant analysis.

Yet another object of the invention is to identify, delineate, andmeasure flaws and assign a clarity grade to a gemstone. This isaccomplished by immersing a gemstone in refractive index liquid,illuminating the stone from the bottom/sides, and imaging it from thetop. Additional illumination from the top, front, and side is obtainedand a stone is rotated to obtain the best image of internal flaws,inclusions etc. The captured image is analyzed by a data processor todelineate and measure any features. The size and the location of thefeatures relative to the size of the gemstone and its cut is used toassign a clarity grade.

Still another object of the invention is to check for fluorescence, itsintensity as well as the characteristics of the radiation emitted as aresult of ultra violet stimulation; This is accomplished by taking twoimages. A stone that fluoresces will yield a first R.G.B. reading (red,green, blue) when illuminated by ultra violet radiation and a secondR.G.B. reading with the ultra violet source disabled. The variations inthe two readings are used to measure the degree of fluorescence, thecolor of visible emission spectra, and a fluorescence grade is assignedbased on this information. This imaging process eliminates the need foran expensive color camera sensitive to low level radiation orintegrating an image over time.

A further object of the invention is to measure brilliance andscintillation of a gemstone. Images are taken from the table side of agemstone. After adjusting for the intensity of illuminant, an average oftotal illumination over the face of a gemstone is used to measurebrilliancy. Images used for brilliancy measurement are also used tomeasure scintillation. This is accomplished by thresholding a gray scaleimage and measuring pixels above a certain minimum level to bedetermined by trade for different gemstones. The ratio of total pixelsexceeding the defined threshold and the area of the face of a stone inpixels is used to calculate the scintillation of the gemstone.

Another objective of the invention is to measure reflectance from thetable of the gemstone, identify surface scratches and describe the shapeand size of the table. For clear stones, a collimated light illuminatesthe table of a stone at an angle; image of the surface reflectance iscaptured and processed. A ratio of the average reflected light to theaverage value of the illuminant measures reflectance. Thresholding isused to identify surface scratches which can be automatically measuredby the number of pixels. A morphological image algorithm is used todetermine the shape and size of the table.

A further objective of the invention is to authenticate a gemstone. Eachstone is identified by the quantified properties as determined by theimaging apparatus, and those values are utilized to identify it. Thesystem is designed to evaluate multiple properties of a gemstone forauthentication. Calculated weight from the apparatus can be compared toscale weight and refractive index of a stone can be calculated. Internalfeatures of a stone can be mapped, described and used in authentication,presence or absence of fluorescence, its intensity and frequency can becalculated, and surface features and textures as described above can beextracted from an image. Filters such as: Chelsea,Waltonhodgkinson-Hanneman, frequency, and polarization filters areplaced in the path of light between an object being analyzed and a lensto separate simulants and synthetics from natural stones.

Yet another object of the invention is to provide a database for storingtext, video, graphic, and audio data corresponding to a plurality ofgemstones. Furthermore, the database is capable of automated search,report generation, automatic input and output of data from othermachines and from the analytical component of the invention. Thedatabase is remotely located from the apparatus to ensure the securityof its contents.

Another object of the invention is to have secure local and wide areacommunication capability to transfer text, video, graphic and audiodata. This capability is used for centralized data processing and tomonitor the performance of remotely distributed devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments of the present invention, will be betterunderstood when read in conjunction with the accompanying drawings inwhich:

FIG. 1 shows a functional block diagram of the gemstone grading systemin accordance with the present invention;

FIG. 2 shows a front view of the imaging apparatus of the gemstonegrading system shown in FIG. 1;

FIG. 3 shows a front sectional view of the interior of the imagingapparatus of the gemstone grading system shown in FIG. 1;

FIG. 4 shows a top view of the imaging apparatus of the gemstone gradingsystem shown in FIG. 1;

FIG. 5 shows a top view of the bottom light assembly of the imagingapparatus of the gemstone grading system shown in FIG. 1;

FIG. 6 is a schematic diagram of the electrical control circuit of theimaging apparatus shown in FIG. 1;

FIG. 7 is a side view of the imaging apparatus in a first imagingposition;

FIG. 8 is a side view of the imaging apparatus in a second imagingposition;

FIG. 9 is a side view of the imaging apparatus in a third imagingposition;

FIG. 10A is a logical flow diagram of the cut analysis method ofoperating the imaging apparatus of FIG. 1;

FIG. 10B is a continuation of the logical flow diagram of FIG. 10showing the color analysis method of operating the imaging apparatus ofFIG. 1; and

FIG. 10C, is a continuation of the logical flow diagram of FIG. 10 thebrilliance, scintillation, flaw and polish analysis method of operatingthe imaging apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An automated gemstone grading and data management system is providedwherein the aesthetic and/or monetary value of a gemstone is determinedrelative to the measured spectral response of light energy incident to agemstone. Gemstones are illuminated by a plurality of light sources suchthat the spectral response of the gemstone is captured as a pixel dataset, gauged, quantified and recorded for future reference via a CCDcamera of an imaging apparatus.

More particularly, the present invention provides a local imagingstation for the automated valuation of gemstones. The local imagingstation is operably linked to an analysis station for communicatingcaptured incident light data sets thereto. The analysis station employsa data processor and model database for assessing the aesthetic and/ormonetary value of gemstones by way of the communicated pixel data sets.Gemstones are subject to a plurality of incident light sources of theimaging apparatus. The spectral response of a gemstone to the incidentlight sources is quantified relative to model pixel data sets of thedatabase and recorded for future reference therein.

The method and associated apparatus for the standardized grading ofgemstones, gauges the spectral response of a gemstone subject to aplurality of incident light sources of the imaging apparatus. Incidentlight energy is captured via the charge coupled device of the imagingapparatus of the local station. The operation of the imaging apparatusis controlled by a local station control data processor and instructionset. The control data processor of the local station is operably linkedto an analysis station, the station includes an analysis data processorand mass storage memory device. The memory device provides storage spacefor the instruction set of the analysis data processor as well asdatabase records.

The data processor of the analysis station provides an instruction setfor facilitating communication with the imaging apparatus, analyzingcommunicated pixel sets, and producing reports of the analysis function.The instruction set includes analytical and statistical image modelswhich extract pertinent objective aesthetic and value attribute indiciafrom the pixel data sets. The reference value database serves as a modelof exemplary gemstone pixel data sets as detected by the imagingapparatus. The database provides a reference for comparing incidentlight data communicated to the analysis station, the model datafunctioning to relate, compare, and distinguish the spectral response ofa gemstone having unknown quality subjected to the illumination protocolof the imaging apparatus. Additionally, the analysis station includes amass storage memory devices for storing the reference value database,analysis instruction set, and report information which may include textas well as visual and audio data. The reports are communicated from theremotely located analysis station to the imaging apparatus by way of atelecommunication network such as a LAN (Local Area Network) or WAN(Wide Area Network) for reproduction at the local station via anattached printer.

The local station includes the imaging apparatus, control processor, andprinter. The control data processor of the local station provides aninstruction set for automating the steps necessary for the precisionpositioning and actuation of the components necessary to operate theimaging apparatus. The data processor has local and wide areacommunication capability for communicating with the data processor ofthe analysis station via a communication port. A preferred embodiment ofthe system and methods in accordance with the present invention will nowbe described with reference to the enumerated drawing figures.

Referring now to FIG. 1, the system includes a local station 8 which isoperably linked by way of a telecommunication network 15 to an analysisstation 14. The local station 8 includes an electronic imagingapparatus, generally designated 5, for imaging a gemstone such as adiamond or pearl. Local station 8 also includes a control data processor10 for controlling the operation of the imaging apparatus 5 by way of aprogrammed instruction set, and a printer 19. The data processorfunction is preferably performed by a general purpose computer, such asa personal computer, including a microprocessor for the processing ofthe imaging apparatus instruction set. The control data processor 10 oflocal station 8 is programmed with one or more suitable networkprotocols to permit it to capture and communicate pixel data sets to theanalysis station 14 with which it is operably linked.

In the preferred embodiment, the general purpose computer includesvolatile RAM (Random Access Memory) and non-volatile ROM (Read OnlyMemory) for facilitating the use of known computer operatingenvironments such as the Windows operating interface. The generalpurpose computer may additionally employ a data management softwareprogram to catalog, format and update communicated reports communicatedfrom the analysis station 14. The interface software enables the visualdisplay of data set reports and appraisals communicated from theanalysis station 14, as well as the manual entry of information to thereports via the data management software. A printer 19 is provided atthe local station 8 for generating reports communicated from analysisstation 14.

Imaging apparatus 5 of local station 8 includes a (CCD) charge coupleddevice 12 for capturing and communicating pixel data sets to the dataprocessor 10. The pixel data sets captured by the processing of gemstone7 within apparatus 5 provide incident light data to the analysis station14. The control data processor 10 of local station 8 communicates thecaptured pixel data sets to the remotely located analysis station 14.

The analysis station 14 includes a data processor 21, nonvolatile memorydevice 25, and printer 27. Analysis station 14 is operably linked by wayof a telecommunication network 15 to local station 8. The data processor21 of analysis station 14 operates the analysis and database instructionset for storing, comparing, and analyzing captured data sets. Thedatabase of analysis station 14 can be remotely queried or updatedutilizing the software of the local station data processor 10. A printer27 is provided at analysis station 14 for generating activity reports,appraisal reports, and the like.

The data processor function of the analysis station 14 is preferablyperformed by a general purpose computer, such as a personal computer ormain frame computer, including a microprocessor for the processing ofthe analysis and database instruction set. The analysis station computeris programmed with one or more suitable network protocols to permit itto obtain pixel data sets from the local station 8 with which it isconnected. In the preferred embodiment, the general purpose computer ofanalysis station 14 includes volatile RAM (Random Access Memory) andnon-volatile ROM (Read Only Memory) for facilitating the use of knowncomputer operating environments such as the Windows operating interface,in addition to mass storage device 25 provided for the storage ofgenerated analysis reports. The processed image data sets enablereliable appraisal of the gemstones in addition to verifying theauthenticity and quality of each gemstone. The analysis station maysimilarly employ data management software and encode networkcommunications with the appropriate application and network layerprotocols to facilitate known electronic commerce standards. The memorydevice 25 of analysis station 14 may include volatile as well asnonvolatile forms of computer memory. Preferably, the database is storedin a non-volatile mass storage device such as a hard disk drive. Copiesof data set reports and appraisals may be transported via portablememory mediums such as floppy disks, CD roms, DAT's, etc. orcommunicated to a local station 8 or other remote backup sites over thetelecommunication network.

In an alternative embodiment, the data processor function 10 of thelocal station 8 may be integrated with the imaging apparatus 5 such thata stand alone imaging and control apparatus is provided. The stand aloneunit functions to combine the general purpose personal computer withthat of the imaging apparatus 5 such that an on board dedicated dataprocessor would be provided for communicating with remotely locatedanalysis station 14 and controlling the operation of apparatus 5.

Imaging Apparatus

Referring now to FIG. 2, imaging apparatus 5 is shown. The imagingapparatus 5 includes housing 2, display 9, status lights 27, access door29, filter arrays 23, 24, and 26, power switch 31, legs 35, powerindicator 33 and output port 16. The entire apparatus 5 is enclosed bythe housing 2; the housing 2 can be easily removed for access to theinside of the apparatus 5. Either plastic or metal may be used for theconstruction of the housing. The housing seals the interior of theapparatus 5 from external light sources. The interior surfaces of thehousing are coated with a non-reflective light absorbing material tolimit reflection of the plurality of lighting elements housed therein.Leveling legs 35 have shock absorbing pads that are used to level thedevice and reduce vibrations. The imaging apparatus 5 employs fan 61 and83 to blow air into the imaging apparatus through air filters tofacilitate air circulation such that dust does not enter and settle intothe apparatus 5, the air circulation also ensures that the ambienttemperature does not exceed operating parameters.

Display 9 is preferably an LCD (Liquid Crystal Display) which provides avisual representation of the placement of a gemstone 7 within imagingapparatus 5 such that the gemstone may be optimally located on a deviceplatform. In a preferred embodiment, the LCD 9 displays instructionsfrom the computer and the images of a stone being analyzed. However, inan alternative embodiment a monitor of an operably linked personalcomputer can perform this function. The status lights 27 are an array ofLED's (Light Emitting Diodes) each one of which correspond to anoperation of the imaging apparatus. The illumination of the appropriateLED indicating the actuation of the corresponding apparatus functionsuch that monitoring troubleshooting is facilitated without removing thehousing 2 of the imaging apparatus 5.

The imaging apparatus 5 is supplied by 120VAC 60 HZ power supplycontrolled by a toggle switch 31. The power switch 31 connects theapparatus 5 with a power source, and LED indicator light 33 is enabledupon powering the apparatus 5 by way of switch 31.

Access door 29 slidably engages the housing 2, providing access to theinterior of imaging apparatus 5 for the placement of a gemstone therein.Filter arrays 23, 24 and 26 slidably engage the imaging apparatus atlocations designed to position the filter elements to block light energyof a preselected frequency from being captured by the internal CCDdevice of the imaging apparatus.

Output port 16 includes an AC power supply connector 37, an RS-232INSTRUMENT port 39, DB 25 COMP control port 41, video port 45, and SCSIport 43.

The AC power supply connector is attached to a power source for poweringthe electrical components of the apparatus 5. The COMP port controls theactuation to different electrical devices as dictated by the instructionset of the data processor 10 of the local station 8. The INSTRUMENT portprovides an auxiliary connection for use with additional gemstonegrading instrumentation. Video port 45 transmits pixel data sets fromCCD camera 12 of the apparatus 5 to the data processor 10 of localstation 8. SCSI port 43 is provided for the connection of computerperipherals such as a local hard disk or zip drive to the apparatus 5.

Referring now to FIG. 3, a side sectional view of the imaging apparatus5 is shown. The imaging apparatus 5 of the local station provides pixeldata sets for transmission to analysis station 14. The data sets arecommunicated in a graphic file format such as TIFF or JPG. The pixeldata sets are incident light images captured by a charge coupled device12 of imaging apparatus 5, such as manufactured by JVC model #TK107OUand an appropriate lens attached thereto. The pixel data sets of lightenergy incident to the gemstone 7 are processed by analysis station 14to analyze these images and extract pertinent information therefrom toproduce an appraisal report on the gemstone 7.

Forward of the lens of CCD 12 is a filter assembly 26 capable of holdingmultiple filters used to block light of a desired spectrum. For example,infrared and ultra violet filters are used to block infrared and ultraviolet light frequencies. Such filters are critical to color andfluorescent analysis as infra red and ultra violet light are invisibleto the human eye but affect readings taken by the CCD camera 12.

For example, a diffraction grating may be used to obtain a spectrum oflight transmitted through or reflected from a gemstone 7 for use in theidentification of simulants; Similarly, a chelsea filter may be utilizedto identify emeralds.

The filter assembly 26 has a ring light 77 to illuminate a stone from afirst direction. Light source 77 is used to detect surface scratches,facet structures, and to perform color analysis of dark stones. An ultraviolet light 64, capable of short, long wave, or black UV illuminationis provided for fluorescent analysis useful in identifying a gemstone 7,detecting treatments, measuring fluorescence, and distinguishingsimulants from natural gemstones.

Imaging Platform

Referring more particularly to FIGS. 3-4, the CCD camera 12 ispositioned to travel between a first location A and a second location B.The points A and B correspond to a first and second positions of alinear positioner 49 which travels along a focal axis 80 (i.e., thex-axis). The linear positioner 49 is driven by servo motor 86 of thecontrol circuitry 110 (shown in FIG. 6). The linear positioner isactuated to move the camera 12 between point A or B as dictated by thedata processor 10 of local station 8. The instruction set of the dataprocessor dictates the actuation of the linear positioner 49 tocompensate for the vertical movement of the gemstone 7 away from thefocal axis. The distance between positions A and B is preselected tocorrespond to the vertical travel distance of the gemstone whenpositioned above or below the focal axis 80. Thus, the camera isrefocused on the gemstone image by varying its horizontal location,however it should be recognized that a camera having an automated lensassembly operably linked to the data processor 10 of local station 8 iswithin the scope of the invention. The linear positioner 49 obviates theneed for cost prohibitive auto focus systems.

Gemstone Stage

A unitary stage 59 travels along a processing axis 105 through threepositions, namely UP, LEVEL, and DOWN. The unitary stage is partiallyshielded by a stage baffle 85. The stage baffle 85 is a partialrectangular enclosure spanning the vertical length halfway between theLEVEL and DOWN and UP positions of the processing axis 105. The baffle85 obstructs light reflectance while passing light along a particularangle of incidence. The baffle enclosure has openings at the endsperpendicular to the processing axis to permit light entry to theenclosure from the top and bottom light sources. Similarly, theenclosure has its camera facing surfaces removed to permit light data topass to the camera 12 at any of the three stage locations. In the LEVELposition, the enclosure surface facing access door 29 is open to permitinsertion of a gemstone 7, as well as the surface facing light source102.

The unitary stage 59 includes light directing means' 55 and 57,motorized Y-axis linear positioner 87 actuated by servo motor 83 ofcircuitry 110, rotatable platform 53, translucent platform portion 51,and stage light 73. The positions of the unitary stage 59, are definedby the alignment of the platform 53 along y-axis positions UP, LEVEL,and DOWN, with the focal axis 80; The LEVEL position defined as beingaligned with the focal axis 80. Light directing means' 55 and 57 areprovided to direct images of gemstone 7 to camera 12 when the platform53 is positioned above or below the focal axis 80. The light directingmeans' 55 and 57 may be specially oriented beam splitters, lenses and/orreflective mirrors. In the preferred embodiment, the light directingmeans' 55 and 57 are a combination beam splitter and mirror. The lightdirecting means' include a mirror and beam splitting portion on itsfacing surface such that either method can be selected for directingimages to camera 7.

A stone to be analyzed is placed within the stage 59 with its table sidefacing platform 53. The vertical movement of the stage along theprocessing axis 105, between the UP, LEVEL, and DOWN positions, isenabled by the motorized Y-axis linear positioner 87. The preferredembodiment of the stage makes it feasible to obtain images of the front,back, top, and bottom of the gemstone 7 from a plurality of lightsources and locations. The stage has a rotatable platform 53 rotated bya servo motor 120 of circuitry 110. The platform 53 rotates atpredetermined intervals to facilitate imaging of the entire gemstonesurface area. The center of the rotatable platform 53 has a transparentwindow 51 on which the gemstone 7 is placed. The transparent window 51,having a transparent surface area boundaries designed to circumscribethe periphery of the gemstone 7 placed thereon. A holding device may berequired to maintain the placement of mounted stones and to hold a stonein place when the rotatable platform 53 is rotated at high speeds. Theplatform is circumscribed by a stage light 73. The stage light 73 can bea ring light or array of light emitting diodes to illuminate theundersides of a gemstone 7.

Positioned below the rotatable platform 53 is a second filter assembly24 with an iris for regulating the light traveling to the transparentwindow 51 of the rotatable platform 53 from below. Additionally, theassembly accommodates filters and or masks used in refractive index andflaw analysis imaging methods. Positioned below the filter assembly 24is a light directing means 57 mounted at a 45′ angle to the horizontal,traveling through the center point of the light directing means isprocessing axis 105 which is aligned with the center point of thetransparent window 51.

When the unitary stage 53 is in the LEVEL position, light data along thefocal axis 80 incident to gemstone 7 is captured by CCD camera 12.

When the unitary stage 59 is moved to the UP position and the centerpoint of the light directing means 57 is aligned with that of the focalaxis 80, light is directed by the means 57 along focal axis 80 and intothe lens of camera 12. This arrangement allows a view of the bottom orthe table side of a gemstone 7.

A light directing means 55 is positioned above the platform at a 45° tothe horizontal with its center point along processing axis 105. Thisconfiguration allows light from the stone side of the window 51 toilluminate a gemstone 7. The reflected light of light directing means 55is redirected to the lens of camera 12 when the stage is moved to theDOWN setting, the center point the light directing means 55 is alignedwith that of the focal axis 80; This arrangement allows a top view ofthe stone. When the stage 59 is in its normal position, and by rotatingthe platform 53, multiple images of the profile, front and back of thegemstone 7 can be taken.

Opposite the camera side of the stage 59, a diffused light source 102provides back lighting used in profiling the silhouette of a gemstone 7,used to extract coordinate values from the corners of a gemstone 7 whenimaging the periphery. For, example a side image is captured with thestage in the LEVEL position, the top and bottom perspectives obtained inthe DOWN and UP positions of stage 59 respectively via light directingmeans 55 and 57.

Referring more particularly to FIG. 5, a bottom light assembly includesring light 90, bottom light 94 and laser light 92. The ring light 90 isa D 55 ring light having a color rendition and an ultra violet componentthat closely resembles North-Daylight at 5500° K. The circularconfiguration ensuring consistent application of the light to theperiphery of the gemstone 7. The ring light 90 is used in color,brilliancy and scintillation analysis and placed in such a mannerrelative to the stone as to create dark field illumination, (i.e.,creating a dark background with respect to the gemstone 7 from thecamera perspective). The bottom light 94 can be any dimmable anddiffusible light source, in the preferred embodiment it is a halogenlight. Bottom light 94 and light 93 are used in clarity analysis.Diffused light 93 is placed off to the side of the processing axis 105and is used in conjunction with light 94 to get a reflection of thetable with the camera 12. Additionally, bottom light 94 and light 93 areused in capturing the morphology of the table of a gemstone 7 for cutanalysis, the table image is also utilized to accurately measure thepolish of the table, its surface characteristics, and match a gemstone 7through its unique sequence or side images. The laser light 92 is usedto align a gemstone 7 on the glass window via LCD display 9, obtainlaser scatter, and to measure refraction.

Above the stage 59 is light source 74 to provide direct lighting of thegemstone 7 useful in observing its top portion. Light source 74 can beany dimmable diffused light. In the preferred embodiment a halogen orLED light source 74 is utilized. Light 74 is used in clarity analysis,surface defect detection, culet analysis, color analysis of dark stonesand pearls and lustre in pearls. Above the light 74 is another filterassembly 23 that can hold a diffuser and one or more filters forblocking light of a preselected frequency. Above the filter assembly 23is a light source 71 used to profile the girdle, match and calculate theperimeter of the gemstone 7, measure the total surface area, and is usedin clarity analysis. Right above the halogen light 71 is a canopy 67that lets warm air out without letting outside light to penetrate theinside of the apparatus 5.

Control Circuit

Referring now to FIG. 6, control and data acquisition circuit 110dictates the actuation of the internal motors and light sources ofapparatus 5. A DC power supply rectifies the AC line current providedthrough switch 31, for components of control and data acquisitioncircuit 110 which require DC power. Control and data acquisition circuit110 includes relays K1-K13, servo controller 83, servo motors 86, 87,and 120, LCD and LED driving circuitry 125, speaker 140, DC fan 61, andAC fan 130.

The relays K1-K13 are selectively actuated to enable the lamp or motorconnected thereto by way of data port 16. The servo motors are driven byservo control unit 83. The actuation of motors and lamps is provided bythe data processor 15 of local station 8 through an interface of dataport 16, preferably the DB-25 COMP port 41. For example, upon receptionof an actuation signal from the data processor 15 for light source 102of apparatus 5, the data port 16 triggers relay K6 to enable lightsource 102.

Speaker 140 provides audible indicia of the execution of instruction byapparatus 5. The audible indicia may be prerecorded descriptive phrasessuch as “color”, “clarity”, and “scintillation.”

Imaging Methods (Level)

Referring now to FIG. 7, a first image capture configuration is shownfor capturing a first set of images, namely, images A1-A19. It should benoted however, that the image capture procedure, lamp and motoractuation sequence can be altered or truncated to accommodate specificgemstones 7 such as pearls which may not possess the full range ofqualities such as table dimensions, clarity, brilliance etc.

The lights and motors of apparatus 5 are controlled by local station 8,specifically apparatus 5 is controlled way of the instruction set of thedata processor 15 of local station 8. The preferred sequence andduration of light and/or motor actuation will now be described hereinfor analyzing a diamond gemstone 7.

At start up, the apparatus 5 is initialized by closing power switch 31.A diagnostic analysis of the lights and motors of apparatus 5 iscompleted by the data processor 15 of local station 8 including thecalibration of dimmable lights to desirable intensities, uponsatisfaction of this test, indicating all devices as functioning, aninstruction set sequence is shown on LCD display 9 or monitor (notshown).

At start up, the laser light 92 is enabled such that a beam of visiblelight is aligned with processing axis 105 to facilitate the placement ofa gemstone 7 on rotatable platform 53. Unitary stage 59 is initializedin the LEVEL position to align rotatable platform 53 with focal axis 80.The camera 12 is set to the “A” position along focal axis 80 position byx-axis linear positioner 49.

A gemstone 7 is prepared for analysis, a cleaning fluid such as alcoholis applied to the gemstone 7 to remove particles and impurities whichmay interfere with the imaging process. Sliding door 29 of apparatus 5is opened and a gemstone 7 is placed at the center of the translucentwindow 51 of platform 53 with the guidance of laser light 92 directedtherethrough. Sliding door 29 is closed and the gemstone 7 is inposition for analysis by apparatus 5.

Imaging begins by disabling laser light 92. A profile image of thegemstone 7 (A1) is obtained by enabling D55 light 90 and light 102,rotatable platform 53 is rotated to obtain the profile of bezel facetsand image (A1) is captured by camera 12 of apparatus 5. The profileimage (A1) is communicated from apparatus 5 to the data processor 15 oflocal station 8 for further processing by analysis station 14.

A second image (A2) is obtained for color analysis by disabling light102, light 90 remains enabled. The resulting image of gemstone 7 iscaptured with camera. Similarly, the second image (A2) is forwarded forfurther processing to analysis station 14. The process of obtainingprofile and color images (A1) and (A2) is repeated dependent of the cutof the diamond as determined by the data processor 10 of local station8.

For example a third image is obtained by rotating the platform 53 by apreset amount, the degree of rotation determined by the instruction setof the data processor 15, enabling light 102, light 90 remains enabledand another image of the profile (A3) is captured by camera 12.

Similarly, a fourth image (A4) is taken by again disabling light 102,light 90 remains enabled and the image is captured by camera 12 forcolor analysis.

For a round brilliant cut diamond the first and second images (A1, A2)are captured from eight locations determined by the preselected rotationof platform 53 resulting in sixteen separate profile and color images(A1-A16). These images are used in cut analysis and for colormeasurement.

Upon completion of the profile and color imaging, light 102 is disabledand fluorescent light 64 is enabled to obtain a fluorescence image A17which is used together with the last captured color and profile image ofset (A1-A16) to check for fluorescence levels, these images may rangefrom (A1) and (A2) to (A15) and (A16) depending on the cut of thediamond. As can be appreciated image (A17) is taken only for thosegemstones with fluorescent qualities.

Image (A18) is captured by disabling all lights, and enabling frontlight 77 to image the front of a gemstone 7, image (A18) is captured bycamera 12. The platform 53 is rotated 180° and another image (A19) iscaptured. Images (A18) and (A19) are used to gauge external surfaceflaws on the sides of a diamond, faceting and the quality of the girdle.

I. Stage Up

Referring now to FIG. 9, a second image capture configuration is shownfor capturing a second set of images, namely, images A21-A24. The secondstage setting is accomplished by moving the stage 59 up along processingaxis 105 by way of y-axis linear positioner 87. Stage 59 is moved upsuch that the center of light directing means 57 is aligned with focalaxis 80 and platform 53 is in the UP position. The camera 12 is movedfrom position “A” to position “B” along focal axis 80 by the linearpositioner 49.

Brilliance and scintillation image (A21) is obtained by enabling D55Light 90. Image (A21) used for brilliance, scintillation and matchinganalysis is captured by camera 12.

Girdle image (A22) is captured by camera 12 by disabling Light 90 andenabling light 71 to capture an image (A22) for girdle measurements.

Table and luster image (A23) is captured by camera 12 by disabling light71 and enabling light 92 and 93 are enabled. Image (A23) is captured foruse in luster analysis and to determine the shape and size of the tablefor cut and matching analysis.

Laser scatter image (A24) is captured by camera 12 by disabling lights92 and 93 and enabling laser light 94 to capture the internal laserscatter in image (A24). This is done to replicate the image capture usedby Gem Print, a proprietary system, for extending support services andis not essential to this invention. Gem Print uses the laser scatterpattern to match gemstone 7 to stones in an existing pixel data base.All lights are disabled prior to the initiation of the third stagesetting.

II. Stage Down

Referring now to FIG. 8, a third image capture configuration is shownfor capturing a third set of images, namely, images (A25 and A26). Inthe third stage setting stage 59 is moved down along processing axis 105by way of y-axis linear positioner 87. The stage 59 is moved down suchthat the center of light directing means 55 is aligned with focal axis80 and platform 53 is in the DOWN position. The camera 12 remains inposition “B” along the focal axis. A combination of lights, namely 74,71 and 73 are turned on to get the best image (A25) which is used toexamine the culet, table facets and surface features. At this point thegemstone 7 is removed from the platform 53, all lights are disabled.

Flaw Analysis/Matching

Prior to flaw analysis, gemstone 7 is removed from the apparatus 5 andthoroughly cleaned. For flaw analysis, image (A26), one of two preferredprocedures may be used. In the first procedure, a gemstone 7 is placedon a glass plate with its underside etched to diffuse light, a smallamount of high viscosity immersion oil is dispensed at the center of theplate and a gemstone 7 is placed on the plate in contact with the oil.The plate is placed above the translucent window 51 and lights 92, 93and 73 are turned on to capture image (A26) for internal flaw analysis.

Another approach is to totally immerse a diamond in a small cruciblewith a diffused base and walls. The crucible is placed on platform 53for capturing image (A26) with camera 12. This method yields a slightlybetter image quality. For small flaws, 5 microns or larger, the lens ofcamera 12 is set to higher magnification and multiple images may betaken by scanning the gemstone 7.

This completes a step by step procedure for capturing images used in thegrading of a diamond. It should be clear that apparatus 5 can be used toobtain other images from the setup described above.

Software Processing

Referring now to FIGS. 10A-10C, there is shown an example of theprocedure by which the images captured by imaging apparatus are obtainedand organized, and more particularly, the manner in which incident lightdata is utilized in the grading and identification of gemstones. Atstart-up, step 200, the processing parameters, constants, and countersof local processor 10 are initialized and the lighting elements of theimaging apparatus are calibrated to ensure consistency in lightinglevels. Each gemstone analyzed by the apparatus produces a set of pixeldata images in accordance with the invention. The images for eachgemstone analyzed are stored in a unique analysis folder in the memoryof local station S. The folder organizes the pixel data images intofiles as captured by the apparatus 5 along with a text file thatcontains information on ownership, eventual results of the analysis, anappraisal report and other pertinent information. The text files may becreated in part by manually entered information via an appropriate userinterface of apparatus 5.

Image data in the file folder of local station 8 is analyzed by the dataprocessor 21 of the analysis station 14. In the preferred embodiment,the file folder or set of image and text files are sent to the analysisstation 14 for processing and compilation in the analysis stationdatabase. The folder and its contents are backed up for data security,thereafter, contents of the folder are analyzed to prepare an appraisalreport based on the communicated pixel images of analyzed gemstones.

Referring now to FIG. 10A, in step 202 the local station 8 creates theunique file folder for the storing of gemstone appraisal data. Theillustrative procedures described herein utilize diamond gemstones.Beginning with step 204, the cut of the gemstone is determined bydefining points about the gemstone periphery. The profile of a diamondis a convex set of pixels of low gray scale values against a backgroundof pixels lighter in color. A change from a light to a darker pixelidentifies a pixel to be on the boundary. Knowledge of the shape of adiamond is utilized with the pixel gray scale values to identify cornerpoints. Thus, in diamond analysis for example, the points define themaximum dimension of the table, girdle and culet. The value of pixelsper millimeter(mm) is known and carats per cubic millimeter is assignedinteractively and is roughly 0.00173801. As such, the dimension of thegemstone is determined by the processor 10 of local station 8 byperforming a plurality of geometric calculations based on the definedconstants and obtained gemstone coordinates. Proceeding to step 206, thefirst cut analysis extracts coordinate data for the corners via theprofile image (A1). The gemstone size coordinates are stored within afile of the folder. Next, in step 208 the gemstone size proportions aredetermined by geometric calculations utilizing the obtained coordinatepoints. A counter, steps 210 and 212, repeats this process for obtainingimages necessary to analyze fancy cut gemstones, up to a maximum ofeight for round fancy cut stones. The process is repeated until allprofile images are processed.

The cut analysis continues in step 214 by defining maximum girdle pointabout the gemstone periphery, the coordinates are saved in step 216, andgirdle size and perimeter are calculated in step 218.

Referring now to FIG. 10B, the final cut analysis includes step 220 fordefining table coordinates. Since the morphology of the table of theround brilliant cut generally follows an octagonal shape, amorphological algorithm is employed to find the corner points. Forcertain fancy cuts and where necessary, a cursor is used to manuallymask the corner points of a table. Step 222 permits the operator toenter this data manually via step 224. The table coordinates are storedwithin a file of the folder stored within the memory of local station 8.The coordinate data is further analyzed as outlined flowchart in steps230 and 232 to calculate the girdle size, table width, table height,culet height, pavilion angle, table angle, girdle thickness and variousratios associated with cut analysis and gemstone appraisal practicesknown to those skilled in the art. Cluster analysis is then used toassign a cut grade based on certain proportional attributes. A databaseincluding diamonds of different proportions and associated cut gradesare used in cluster analysis. The cluster analysis assigns a cut gradebased on the proximity of a gemstone to a cut grade in multidimensionalspace.

Gemstone color analysis begins with step 234 and is done by obtainingaverage R.G.B. (red, green, blue) values from color images (A2, A3, A6.. . ) in the image pixel region delineated by the girdle and the tablefacets, by sampling the color of a smaller region a more predictable andaccurate color reading is obtained. Steps 236 and 238 provide the optionof manually entering the R.G.B. values. The R.G.B. image sets are storedwithin a file of the gemstone analysis folder, step 240. The number ofR.G.B. images taken is determined by a counter in steps 242 and 244.

Diffraction of light caused by such gemstones as diamonds skews theR.G.B. color readings by misrepresenting the body color of the gemstone.Furthermore, the diffraction of the light energy into spectralcomponents increases a standard error in the R.G.B. average. Thesoftware of the data processor 21 of analysis station 14 compensates forthis by removing outlier value images from the statistical analysis.Thereafter, an average of the R.G.B. pixel intensity values iscalculated in step 246.

Referring now to FIG. 10C, average R.G.B. values are additionallyobtained from the gemstone color image under ultra violet radiation viastep 248, image (A17). The difference between the average R.G.B. valuewithout ultra violet radiation and under ultra violet radiation are usedto determine the presence of fluorescence in step 250. Fluorescencedevalues diamonds. This analysis is done using a statistical model.Likewise, R.G.B. values from the color images are transformed to C.I.E.,L.A.B., and L.U.V. coordinates. Before assigning a color grade, flawanalysis is performed in step 252. Flaw identification may be performedmanually as illustrated by steps 254 and 256.

A processing algorithm is used for flaw analysis. A combination ofthresholding and filters is used to highlight internal flaws,inclusions, pin points etc. The size and location of these flaws ismeasured. Internal flaws are identified by the algorithm and saved in afile (A27). A clarity grade is assigned based on the size of the flawscompared to the overall area of the face of a stone weighted by itslocation; flaws near and within the boundaries of a table diminish thevalue more than flaws that are farther away from the surface and closerto the girdle area. Proceeding to step 258 the flaw data is storedwithin a file of the analysis folder. Flaws are identified and markedand a gemstone image file (A28) is created in step 262. Images (A9),(A10), (A25), and (A26) are analyzed in step 260 for determininggemstone brilliance, scintillation, and polish analysis. This approachis taken to get as much information as possible to ascertain if thesystem has analyzed the same gemstone.

To do brilliancy analysis, average R.G.B. values are extracted from thebrilliancy image using a processing algorithm. C.I.E., standard L.A.B.,and L.U.V. tri-stimulus coordinates are calculated adjusting forincident light intensity. A ratio of the average gray value and astandard is used to calculate brilliancy. Scintillation is measured byfirst thresholding the image and then calculating the total number ofpixels that have an average gray scale value above the threshold level.A ratio of these pixels divided by the total number of pixels on theface of a stone are used to measure scintillation. The higher thenumber, the greater the scintillation value. Polish of the table isdetermined by extracting the average R.G.B. values from the table imageA23. The average R.G.B. values are adjusted for the incident light. Apolish grade for the table is assigned by comparing the adjusted R.G.B.values to a standard. Once the flaw, brilliance, scintillation, andpolish analysis are completed a search is done of the database ofanalysis station 14 to determine the existence of a record which wouldindicate any prior analysis of the gemstone, or an indication whetherthe gemstone has been included in a lost or stolen record field of thedatabase for matching. A hierarchical search technique is used to reducesearch time considerably in steps 264 and 266. If more than one gemstoneis identified by the search, comparison is made by the data processor toestablish a perfect match. Ideally, only after this step is completed, acluster or linear discriminant model is used to assign color based ontri-stimulus coordinates, weight of a diamond, flaws, and fluorescencein step 268. For newly cut diamonds, searching the database is obviouslyunnecessary. Results of analysis are saved and a report is printed orsent to the local station 8 which requested the analysis.

In addition to evaluating gemstones, the analysis station 14 matches thecharacteristics of the analyzed gemstones 7 to characteristics ofgemstones previously analyzed by the apparatus 5 and stored in thedatabase. Moreover, the database can be queried to inventory gemstones 7possessing a certain characteristic and/or price range as the databasemaintains current market price information used in the appraisal ofgemstones. The analysis station 14 can perform grading, matching,identification, sorting, and appraisal functions independently or in anyspecified combination and communicate these reports as a multimediapresentation to local terminals.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation. There is no intention in the use ofsuch terms and expressions of excluding any equivalents of the featuresshown and described or portions thereof. It is recognized, however, thatvarious modifications are possible within the scope of the invention asclaimed.

1. A system for generating, maintaining, and retrieving characterizinginformation about gemstones comprising: a first illumination sourcedisposed for illuminating a gemstone from a first aspect thereof; asecond illumination source disposed for illuminating the gemstone from asecond aspect thereof; electronic camera means for viewing the gemstoneand for generating a first electronic signal corresponding to a firstphysical characteristic of the gemstone when illuminated by said firstilluminating source and for generating a second electronic signalcorresponding to a second physical characteristic of the gemstone whenilluminated by said second illuminating source; electronic dataprocessor means operatively connected to said electronic camera forreceiving the electronic signals, for controlling the operation of saidelectronic camera to generate electronic signals corresponding to atleast two different physical characteristics of the gemstone, and foranalyzing the electronic signals to provide data files containinginformation identifying said first and second physical characteristicsof the gemstone; data storage means operatively connected to saidelectronic data processor means for storing the information identifyingthe first and second physical characteristics of the gemstone, and foranalyzing the electronic signals to provide data files containinginformation identifying said first and second physical characteristic ofthe gemstone; data storage means operatively connected to saidelectronic data processor means for storing the information identifyingthe first and second physical characteristics in a database of gemstoneidentifying information for a plurality of known gemstones; and meansfor comparing the identifying information of the viewed gemstoneprovided by said electronic data processor with the identifyinginformation of a known gemstone retrieved from said data storage deviceso that the gemstone viewed by the electronic camera means can beaccurately identified from said database of gemstone identifyinginformation.
 2. A system as set forth in claim 1 comprising wherein theelectronic data processor means comprises light control means forcontrolling the first and second illumination sources to illuminate thegemstone with the one or both of the first and second illuminationsources.
 3. A system as set forth in claim 2 further comprising meansfor displacing the gemstone relative to said electronic camera means andwherein the electronic data processor means comprises means forcontrolling said electronic camera and said displacing means forcapturing a profile image and a color image of the gemstone viewed bysaid electronic camera means.
 4. A system as set forth in claim 3comprising means for capturing, multiple profile and color images of thegemstones by said electronic camera means.
 5. A system as set forth inclaim 2 further comprising means for capturing a fluorescence image ofthe gemstone with said electronic camera means.
 6. A system as set forthin claim 2 further comprising means for displacing the gemstone relativeto said electronic camera means and wherein the electronic dataprocessor means comprises means for controlling said electronic camerameans and said displacing means for capturing a brilliance andscintillation image of the gemstone with said electronic camera means.7. A system as set forth in claim 6 further comprising means forcapturing a girdle image of the gemstone with said electronic camerameans.
 8. A system as set forth in claim 6 further comprising means forcapturing a table and luster image with said electronic camera means. 9.A system as set forth in claim 6 further comprising means for capturinga culet image of the gemstone with said electronic camera means.
 10. Asystem as set forth in claim 6 further comprising means for capturing atable facet image of the gemstone with said electronic camera means. 11.A system as set forth in claim 6 further comprising means for capturinga surface feature image of the gemstone with said electronic camerameans.
 12. A system as set forth in claim 2 further comprising means forcapturing a laser scatter image of the gemstone with said electroniccamera means.